Motion assistance system for wheelchairs

ABSTRACT

The presently disclosure describes a motion assistance system for a wheelchair, for example, a powered drive wheel system that can continually drive a wheelchair in a circular or elliptical path. The motion assistance system comprises a mounting mechanism attachable to one or more structural elements of the wheelchair, and a drive linkage pivotable with respect to the mounting mechanism. A drive wheel can be mounted to an end of the drive linkage such that the drive wheel contacts the ground when installed on the wheelchair. The drive wheel comprises a plurality of lateral rollers positioned radially about the circumference of the power drive wheel. The lateral rollers can rotate about an axis tangential to the circumference of the drive wheel in order to facilitate driving the wheelchair in a radial direction.

RELATED APPLICATIONS

This application makes reference and claims priority to U.S. patentapplication Ser. No. 14/830,286, filed Aug. 19, 2015, and titled “MotionAssistance System For Wheelchairs,” which claims priority to U.S. patentapplication Ser. No. 14/053,047, filed Oct. 14, 2013, and titled “MotionAssistance System For Wheelchairs,” which claims priority to U.S.Provisional Patent Application No. 61/782,487, filed Mar. 14, 2013,titled “Motion Assistance System For Wheelchairs.” U.S. ProvisionalPatent Application No. 61/782,487 and U.S. patent application Ser. Nos.14/053,047 and 14/830,286 are hereby incorporated by reference in theirentirety.

BACKGROUND

Manual wheelchairs are the primary mode of locomotion for millions ofpeople around the world. Upper limb pain and injury is very common amongthese manual wheelchair users and can severely impact mobility,independence and quality of life. The most common types of injury areimpingement syndrome of the shoulder and carpal tunnel syndrome of thewrist. Upper limb pain and injury is an emotionally, physically andfinancially costly problem.

Wheelchair propulsion is one activity that has been associated with thedevelopment of these upper extremity injuries. It is recommended thatusers reduce how hard they push on the handrim and to do it lessfrequently in order to reduce the stresses of propulsion on the upperbody.

Power attachment units can mount to manual wheelchairs to assist inpropulsion. An example of one such power add-on is disclosed in U.S.Pat. No. 4,759,418, which is incorporated herein by specific referencefor all purposes, employs a linkage system that mounts to the wheelchairframe and trails in between the two rear wheels. An electric motorpowers a drive wheel that is controlled by a push button located withinreach of the user. This type of design, not common to all powerattachments, also employs a steering bar that attaches to the frontcasters in order to guide the wheelchair when being driven by the poweradd-on. These electric drive attachments are known to be successful inhelping to reduce the physical effort needed for propulsion. A drawbackis that these types of systems completely eliminate the need for pushingbecause the user drives the wheelchair, rather than maneuvers it throughpushes. In this situation, the user does not benefit from the physicalexercise of manual propulsion or the psychological benefits of not beingdependent on the device for transportation.

Another example of a power attachment device is a push activated powerassist wheels. These combine the benefits of manual push operation bythe user and power assistance to reduce the demand on the user's upperextremities during propulsion. Push activated power assist wheels,similar to those disclosed in U.S. Pat. No. 5,818,189, which isincorporated herein by specific reference for all purposes, are batterypowered wheels that employ either force and torque sensors, or both, tomeasure the force applied to the handrims from the user and amplify thatforce through the use of motors embedded in the wheels to drive thewheelchair forward or backward. This technology has been shown to have anumber of positive effects on wheelchair users, including reduced energyexpenditure, reduced push cadence, reduced muscle activation, decreasedrange of motion, easier hill climbing, increased propulsion speed andreduced pain during propulsion for those users already experiencingpain.

The drawback with this approach is that the employment of force andtorque sensors to recognize and quantify the amplitude of the pushsignificantly complicates the design. The handrims must be mounted tothe wheel hubs, instead of the wheel rim as in typical manualwheelchairs, causing a significant increase in complexity. Added costand weight of these devices then becomes inherent when this type ofapproach is taken. Additionally, because measurements are focused on thehandrim, hazardous situations can be escalated by the assistive power.Accordingly, there is a need for power assist system that addresses theissues of these devices.

Another drawback with power attachment devices is that it the powerattachment wheels can be difficult to maneuver the wheelchair aroundchairs. For example, a typical wheel is capable of only moving in onedimension (i.e., forward and backward). When a wheelchair is forcedaround a turn, however, the power attachment wheel will be moving in aradial direction. This can cause added friction between the wheel andthe ground on turns, thereby making maneuverability more difficult.Accordingly, there is a need for a motion assistance system forwheelchairs that provides a power drive wheel that can drive awheelchair in a radial direction.

SUMMARY

The present disclosure describes a motion assistance system for awheelchair. In certain aspects, the motion assistance system comprises amounting mechanism that can be attachable to one or more structuralelements of the wheelchair. The motion assistance system can alsoinclude a drive linkage that is pivotable, or capable of pivoting, withrespect to the mounting mechanism. The motion assistance system alsocomprises a drive wheel mounted to an end of the drive linkage. In thismanner, the drive wheel contacts the ground when it is installed on thewheelchair. The drive wheel comprises a plurality of lateral rollerspositioned radially about the circumference of the power drive wheel.The lateral rollers are rotatable about an axis tangential to thecircumference of the drive wheel. This can facilitate the motionassistance system to drive a wheelchair in a radial direction. Forexample, in certain embodiments of the present technology the powerdrive wheel is capable of continually driving a wheelchair in a circularor elliptical path.

Certain aspects of the present technology provide a motion assistancewheelchair. For example, certain embodiments include a wheelchair havinga seat and at least two rear wheels. The wheelchair can include amounting mechanism that is attached, or attachable to one or morestructural elements of the wheelchair. The wheelchair can also include adrive linkage that is pivotable with respect to the mounting mechanism.In certain embodiments, a drive wheel can be mounted to an end of thedrive linkage such that the drive wheel contacts the ground wheninstalled on the wheelchair. The drive wheel can comprise a plurality oflateral rollers, which can be positioned radially about thecircumference of the power drive wheel. The lateral rollers can berotatable about an axis tangential to the circumference of the drivewheel in order to facilitate driving of the wheelchair in a radialdirection, for example.

Certain aspects of the present technology provide a motion assistancesystem for driving a wheelchair. The system can include, for example, amounting mechanism comprising an expanding connector bar. The mountingmechanism can be removably attachable to a wheelchair. For example, themounting mechanism can be attached to a structural element of awheelchair, such as a wheel axle. The motion assistance system can alsoinclude a drive linkage that is pivotable with respect to the mountingmechanism, and a drive wheel mounted to an end of the drive linkage suchthat the drive wheel makes contact with the ground when installed on thewheelchair. The drive wheel comprises a plurality of lateral rollerspositioned radially about the circumference of the power drive wheel.The lateral rollers can be rotatable about an axis tangential to thecircumference of the drive wheel to facilitate lateral movement of thedrive wheel while driving the wheelchair forward. In some aspects, themotion assistance system can include a motor for driving the drivewheel, and a remote control for controlling the motor. For example, theremote control can comprise a wrist band and an activation buttonpositioned at an inner wrist location of the wrist band.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a side view of a wheelchair equipped with a motionassistance system in accordance with at least one embodiment of thepresent technology.

FIG. 2 shows a rear angled view of a wheelchair with the right wheelremoved and a mounting mechanism for a motion assistance system.

FIG. 3 shows a drive linkage of a motion assistance system attaching toa mounting mechanism of a wheelchair.

FIG. 4 shows a drive linkage of a motion assistance system attaching toa mounting mechanism of a wheelchair.

FIG. 5 shows a drive linkage of a motion assistance system attaching toa mounting mechanism of a wheelchair and angled downward.

FIG. 6 shows a front angled view of wheelchair with the right wheelremoved, the wheelchair equipped with a motion assistance system and abattery button interface.

FIG. 7 shows a front angled view of a wheelchair equipped with a motionassistance system and a remote control interface.

FIG. 8 shows a hand remote interface for use with a wheelchair with amotion assistance system.

FIG. 9 shows a wrist remote control interface for use with a wheelchairwith a motion assistance system

FIG. 10 shows a front angled view of a wheelchair equipped with a motionassistance system and a pushrim remote control.

FIG. 11 shows a close up view of a pushrim remote control for use with awheelchair.

FIG. 12 shows a close up view of another pushrim remote control for usewith a wheelchair.

FIG. 13 shows a front angled view of a wheelchair equipped with a motionassistance system and remote brakes for turning the wheelchair.

FIG. 14 shows a rear angled view of a wheelchair with the right wheelremoved, the wheelchair having a motion assistance system attached by anexpanding connector bar.

FIG. 15 shows a rear view of a wheelchair having a motion assistancesystem attached by an expanding connector bar.

DETAILED DESCRIPTION

The presently disclosed technology relates generally to a motionassistance system for manual wheelchairs. More specifically, the presenttechnology relates to a feature that employs a wheel, for example, thatis configured to move sideways and and/or laterally. In certainembodiments, the present technology can operate with a system thatemploys motion-based sensing for recognition of user breaking and asmart drive feature for such a power assist system that assists in themobility of a power assist driven wheelchair.

In certain embodiments, the presently described motion assistance systemcan operate in connection with a motion-based power assist system, forexample, the system described in U.S. patent application Ser. No.13/543,598 (“the '598 application”), which is hereby incorporated byreference in its entirety. However, the motion assistance system canalso operate in connection with a wheelchair that is not equipped with amotion-based power assist system.

The motion assistance system can include a drive wheel or a power drivewheel (e.g., a drive wheel including a motor) that makes contact withthe ground, and a mounting mechanism 140 (also referred to herein as amounting attachment or a hitch) that clamps to an axle bar of thewheelchair. The motion assistance system can also include a drivelinkage, which can be pivotally attached to the wheelchair, for example,to a structural element, or to an axle or an axle bar of a wheelchair,through a mounting mechanism. In this manner, the power drive wheel canmount to a distal end of the drive linkage, and the mounting mechanism140 can pivotally attach to the drive linkage on the opposite end of thepower drive wheel. The present technology is explained in more detailbelow in connection with FIGS. 1-15.

FIG. 1 depicts the side view of a wheelchair 10 equipped with a motionassistance system 100 of the present technology. The motion assistancesystem 100 can include a drive unit 102, which can comprise a drivewheel 110 and a drive linkage 120, for example. The drive unit 102 canbe a power drive wheel, for example, that includes a motor for drivingthe drive wheel forward and/or backward. The drive unit 102 can includea motion-based power assist system such as the system disclosed in the'598 application, for example.

The drive wheel 110 is pivotally mounted to a drive linkage 120 so thatthe drive wheel 110 can rotate freely to maintain traction while drivingthe wheelchair 10. In certain embodiments, the drive linkage 120 and/orthe drive wheel 110 can comprise a motor, for example, an electricmotor, that drives the drive wheel 110 and, in turn, the wheelchair 10.The drive linkage 120 can attach to a mounting mechanism 140 (e.g., amounting attachment or a hitch), which can be attachable to one or morestructural elements of a wheelchair. In certain embodiments describedherein, the drive linkage 120 can be attachable and detachable from themounting mechanism 140 via a hinge, for example. In turn, the mountingmechanism 140 can be clamped to a support bar, an axle bar, or an of thewheelchair 10.

The drive wheel 110 has side facing lateral rollers 112 that allow anoperator to turn the wheelchair with relative ease using the pushrims 14on the wheels 12 of the wheelchair 10 while the drive unit 102 is innormal operation. The angle θ of the drive linkage 120 with respect tovertical can vary in different embodiments and depending upon thespecific use. However, in certain embodiments, the motion assistancesystem 100 can operate efficiently on a flat surface when the angle θ isabout 40 degrees from vertical.

FIG. 1 also shows an extra battery 30, which can be a part of the motionassistance system used to power the drive unit 102, for example, themotor of the drive unit. The battery 30 can be installed, for example,at a location at, around, or under an armrest 25 of the wheelchair 10.In some embodiments, one or more batteries 30 can be installed orlocated at any position that allows for the battery 30 to be in anelectrical connection with the drive unit 102, such that the battery 30can power a motor of the power drive wheel.

FIG. 2 shows a rear angled view of a wheelchair 10 having the rightwheel removed. The wheelchair 10 has a mounting mechanism 140 attachedto a support bar 40 (or an axle bar or axle tube) of the wheelchair. Themounting mechanism 140 can be, for example, a hitch or other attachmentdevice capable of clamping or otherwise attaching to a structuralelement of the wheelchair 10, and to a drive linkage 120 of a drive unit102. As shown, the mounting mechanism 140 can be on an axle tube or on alinkage that spans across the side frames of a folding frame wheelchair.While this embodiment depicts a mounting mechanism that is separate fromthe drive unit 102, thereby allowing the drive unit 102 to attach to thewheelchair 10, it should be appreciated that in certain embodiments, themounting mechanism 140 can be a part of the drive unit 102.

FIGS. 3-5 demonstrate an example of how a drive linkage 120 of a driveunit 102 can attach to a mounting mechanism 140 (e.g., mountingmechanism 140 of FIG. 2) of a wheelchair. In FIG. 3 the drive linkage120 approaches the mounting mechanism 140 at an angle that isapproximately parallel with the ground, or angled such that the drivewheel 110 is higher than the mounting mechanism 140. The shape of thedrive linkage unit interface 130, which can include a hook 132, allowsthe drive linkage 120 to be set onto the mounting mechanism 140. Themounting mechanism 140 can have a slot, bar, or other attachmentmechanism adapted to mate and/or connect with the drive linkage unitinterface. For example, the mounting mechanism 140 can have a connectorbar 143 having round ends and with flat sides, adapted to be surroundedand/or grabbed by a hook 132. In some embodiments, the mountingmechanism 140 comprises a flat edge 142, which can help stop the driveunit from rotating under the wheelchair.

The drive wheel 110 (not shown in FIG. 3) can be mounted to the distalend of the drive linkage 120 so that the drive wheel 110 can makecontact with the ground when the drive linkage is properly attached tothe mounting mechanism 140. The drive linkage unit interface 130 can beequipped with a spring loaded clip 134 to close off the hook 132 whenattached to the mounting mechanism 140 so as to prevent the hook 132from unintentionally becoming detached from the mounting mechanism 140,for example.

FIG. 4 shows the drive linkage 120 lowered such that the drive linkageunit interface 130 engages with the mounting mechanism 140. Morespecifically, FIG. 4 shows the connector bar 143 of the mountingmechanism 140 surrounded by the hook 132 and the clip 134 of the drivelinkage interface 130. As shown in FIG. 4, the drive linkage 120 isstill approximately parallel with the ground or angled so that the drivewheel 110 is slightly higher than the mounting mechanism 140 after theinitial connection.

FIG. 5 shows the drive linkage 120 rotated and effectively locked and/orpositioned into place with respect to the mounting mechanism 140. Whilein place, however, the drive linkage 120 can rotate freely to maintaintraction with the ground. FIG. 5 shows the drive linkage 120 rotateddownwards such that the power drive wheel would be in contact with theground.

As shown in FIGS. 1, 6-7, 10, and 13-15, the drive wheel 110 can includemultiple lateral rollers 112 positioned radially about the circumferenceof the power drive wheel 110. The lateral rollers 112 can be rotatableabout an axis that is tangential to the circumference of the drive wheel110 such that, when the drive wheel 110 is placed on a surface, thedrive wheel can freely slide in a direction parallel to the rotationalaxis of the drive wheel 110. Because the lateral rollers 122 rotatefreely about an axis tangential to the circumference of the drive wheel110, the drive wheel can sliding in a direction parallel to the centeraxis of the drive wheel 110 while in contact with the ground. Thelateral rollers 112 can also provide traction between the drive wheel110 and the ground when the drive wheel 110 is driving or rolling aboutthe center axis of the drive wheel 110. In this manner, the drive wheel110 can of drive the wheelchair forward by rotating about the centeraxis of the power drive wheel.

In certain embodiments, the motion assistance system 100 can be mountedto a wheelchair such that the drive wheel 110 contacts the ground midwaybetween two wheels 12 of the wheelchair 10. The drive linkage 120 can bemounted and angled so that rotation of the drive wheel 110 createsincreased traction with the ground when the drive wheel is powered(e.g., by a motor) to drive the wheelchair forward. In this manner, thelateral rollers 112 facilitate the drive wheel 110 to slide in a lateraldirection while also driving the wheelchair 10 forward. Accordingly,with this feature, the motion assistance system 100 can be capable ofcontinually driving the wheelchair 10 in a radial direction.

The drive wheel 110 can include more than one wheel. For example, thedrive wheel 110 can comprise two wheels (e.g., 110 a and 110 b as shownin FIG. 6), each wheel (110 a and 110 b) comprising a plurality oflateral rollers 112 about the circumference of the wheel 110. In certainembodiments, the lateral rollers 112 can be a cylindrical shape or abarrel shape. The lateral rollers 112 may have a length approximatelytwo times larger than the diameter. The drive wheel 110 can include adifferent number of lateral rollers depending on the size, shape, andintended operation of the drive wheel 110 and/or the motion assistancesystem 100. For example, in certain embodiments, the drive wheel 110 caninclude eight or sixteen lateral rollers 112.

The lateral rollers 112 can be arranged such that at least one lateralroller is in contact with the ground when the drive wheel 110 is incontact with the ground. For example, in some embodiments (e.g., asshown in FIGS. 6, 14, and 15), the drive wheel 110 can comprise twodrive wheels (110 a and 110 b), each drive wheel having lateral rollers112 spaced apart from one another to allow free rotation of the rollers.The two drive wheels 110 a and 110 b can be offset such that at leastone lateral roller 112 from one of the wheels 110 a or 110 b is incontact with the ground regardless of the rotational position of thedrive wheel 110. That is, in circumstances where the lowermost positionof wheel 110 a is an space between lateral rollers 112, then thelowermost position of wheel 110 b will be a lateral roller 112 that isin contact with the ground.

The lateral rollers 112 can roll about an axis that is tangential to thecircumference of the drive wheel 110. Because the lateral rollers 112 donot pivot about an axis perpendicular to the planar surface of the drivewheel 110, the lateral rollers 112 still provide traction when the drivewheel 110 is driving the wheelchair 10 forward. In this manner, when thedrive wheel 110 is in contact with the ground, the lateral rollers 112allow the wheel to slide in a lateral, or sideways direction, while atthe same time allowing the drive wheel 110 to grip the ground withenough traction to drive the wheelchair 10 forward. This feature can aidin the mobility and maneuverability of a wheelchair equipped with apower assist system, as it can enable the system to continually drivethe wheelchair 10 in a radial direction. For example, the motionassistance system 100 can allow a power assist system (e.g., a powerassist system described in the '598 application) to drive the wheelchair10 along a circular or elliptical path. This can help a user move awheelchair 10 around a turn, or move along a track, for example.

Certain embodiments of the present technology also relate to a motionassistance system for driving a wheelchair using a control switch. Forexample, in certain embodiments of the present technology, a motionassistance system can drive the wheelchair by pressing a button,activating a switch, or pressing onto a throttle to accelerate ordecelerate a wheelchair to a desired velocity. In this manner, themotion assistance system differs from a motion-based power assist system(e.g., the system of the '598 application) because the power assist isbased on the activation of a switch, rather than the implementation ofinitial motion of the wheelchair. A user of the present motionassistance system can activate the system and then steer the wheelchairwith his or her hands by applying pressure to the handrims of thewheelchair. Along these lines, the motion assistance system caneffectively operate with the motion assistance system and the relatedpower drive wheel with lateral rollers. That is, by applying pressure tothe handrims of a wheel, the wheelchair will change angles, but becausethe power drive wheel can freely move laterally or sideways, thewheelchair can continue driving around a turn in a radial direction.

The motion assistance system can include a control switch located on oraround the seat of the wheelchair. For example, FIG. 6 depicts a controlswitch 200, or a button, on the front of an extra battery. This controlswitch 200 can be used to directly control the motor of the drive unit102. The control switch 200 may be located in the center of a frontsurface of the seat of the wheelchair 10. An operator can thereforepress and/or hold the button of the control switch 200 to accelerate ordecelerate the wheelchair 10 to a desired speed. By pressing the buttonof the control switch 200, the drive unit 102 can respond byaccelerating or decelerating as instructed by the user.

The control switch 200 can utilize multiple control schemes. Forexample, in one control scheme, the operator can press and hold a buttonuntil a desired speed is reached, and then release the button to cruiseat that speed. The wheelchair can then continue to cruise at that speeduntil the operator issues a command to change this, for example, bypressing the button again to momentarily turn off the motor. In anothercontrol scheme, control switch 200 can be configured to operate at aseries of predetermined speeds. For example, while stationary, the usercan press and hold the button to step up to the first speed step. Theoperator can continue to press the control switch 200 to step up thespeed to various levels until a desired speed is reached. The operatorcan also press or hold the control switch for a certain time to turn offthe motor.

In certain embodiments of the present technology, the control switch canbe a remote control. For example, FIG. 7 depict embodiments of a remotecontrol 300 mounted to a wheelchair 10 equipped with a motion assistancesystem 100 of the present technology. The remote control 300 can bemounted to a structural element or the frame of the wheelchair 10, forexample, on the push handles 11 for easy operator access. The buttons onthe remote control 300 can allow a user to start and stop the motor, andalso to control the speed of the motor. For example, the remote control300 may be equipped with +/− buttons to step the speed up or down. Thebuttons can also be configured so that a press can make a large speedchange upwards or downwards.

In certain embodiments, the remote control can be equipped with athrottle that allows a user to set a more precise speed based on acontrol switch position. For example, FIG. 8 shows a hand remote control310 that allows a user to directly control the speed of the drive unit102 using a thumb throttle 312, which can be a 3-way control togglerocker and push-in button, for example. This feature can allow a user todirectly control the speed of the drive unit 102 while still being ableto steer the wheelchair 10. For example, a user can set the thumbthrottle 312 to a desired speed by rotating the thumb throttle in aclockwise/counterclockwise manner, and then press the throttle button312 inwards to turn the motor off. The hand remote control 310 can bedesigned to attach to the armrest or other structural element of thewheelchair 10. The hand remote control 310 can also be designed to beheld in, or wrap around the hand and/or one or more fingers of a user.The hand remote control 310 can come in a variety of sizes and shapes.For example, the hand remote control 310 can be a 2-finger band thatcomes in an extra-small, small, medium, large and extra-large size,depending on the size of the operator's hand.

FIG. 9 shows another embodiment of a remote control 330 in accordancewith an embodiment of the present technology. More specifically, FIG. 9shows a wrist remote control interface 330 for use with a wheelchair 10using a motion assistance system 100. The wrist remote control 330 canbe worn on the wrist or forearm of a user, for example, and used toaccess different operating modes of a motion assistance or powerassistance system. The wrist remote control 330 can comprise a band 360,which can comprise compliant plastic, for example, making the band 360stretchable and/or bendable, to make it easy to put the wrist remotecontrol 330 on and off. The band 360 can also have a non-slip portion362 on an inner surface designed to keep the wrist remote control 330from slipping out of position on the wearer. For example, the non-slipportion can comprise a material such as rubber that provides frictionbetween the writ band 360 and the arm/wrist of a wearer withoutsacrificing comfort to the user.

The wrist remote control 330 can also comprise an activation button 370,which can be depressed to activate certain functionality of the motionassistance system. For example, the activation button 370 can be pressedto change the mode of a drive unit 102, to turn a motor on or off, or toadjust the speed of the drive unit 102, for example. The activationbutton 370 can be located at an inner wrist location on the band 360 sothat a user can simply press that portion of the wrist against astructural element of the wheelchair to depress the button 370. In thismanner, a user can activate the wrist remote control 330 without havingto remove his or her hands from the wheels of the wheelchair, forexample. In some embodiments, the wrist remote control 330 can be usedto activate and/or deactivate a power assistance and/or motionassistance system; however, in some embodiments, the wrist remotecontrol 330 can be used to only provide a single function, for example,to deactivate the drive unit 102, or as an emergency brake, for example.

The wrist remote control can also comprise one or more warning and/orstatus lights. For example, FIG. 9 shows a wrist remote control 330 witha status LED light 380, which can indicate a certain status of the wristremote control 330 or the motion assistance system 100 controlled by thewrist remote control 330 for example. FIG. 9 also shows a wrist remotecontrol 330 with a warning LED 382, which can indicate a low battery, abattery charging indicator, or an error signal, for example. In certainembodiments, the status/warning lights 380 and 382 can be differentcolors. For example, the status light 380 can be a green LED light, andthe warning light 382 can be a red LED light. In certain embodiments,each of the lights 380 and 382 can take on two or more colors, forexample, red, yellow, green, blue, orange, white, or purple. In someembodiments, the status/warning lights 380 and 382 can generate signalsin the form of a blinking or flashing pattern as a way to distinguishbetween certain status or warning signals. For example, in someembodiments, warning light 382 can blink in a particular pattern toindicate one of a number of potential problems with the wrist remotecontrol and/or the motion assistance system 100.

In some embodiments, the motion assistance system 100 can be operated bya pushrim remote control. FIG. 10 shows an embodiment of a wheelchair 10equipped with a motion assistance system 100 and a pushrim control 400,which can be, for example, a remote control. The pushrim control 400 canbe attached to a wheel 12 of the wheelchair 10 in a complaint way tomeasure a forward push and rearward brake movement of the wheel 12.

FIG. 11 shows a pushrim control 400 on a pushrim 14 of a wheel 12 of awheelchair 10. The pushrim control 400 is connected to a pushrim tab 15of the wheelchair, and comprises complaint members 420, which can thatbias the pushrim 14 to a neutral position. The pushrim control 400 canalso include a switch 430, or a displacement or force sensor. In thismanner the pushrim control 400 allows an operator to set the motor speedof the motion assistance system 100 based on the sensed forward push ofthe pushrim 14. The pushrim control 400 can operate based on the time ofthe push, the force of the push and/or the displacement of the wheel.For example, an operator can activate forward movement or forwardacceleration by pushing the pushrims 14 forward, or activate adeceleration or a motor stop/shutoff by moving the pushrims 14 rearward.

FIG. 12 shows another view of the pushrim remote control 400. Here, thepushrim control 400 is configured to sense data transmitted wirelesslyand or remotely to the drive unit 102 via bluetooth or other similartechnology, for example. A wheelchair 10 employing the pushrim remotecontrol 400 of FIG. 12 can include a battery and circuitry housed withinsensor mounts, or in a single location with wires that connect the motorof a drive unit 102 to the sensors, for example. More specifically, FIG.12 depicts a side view of a pushrim control 400. As shown, the pushrimcontrol 400 involves a compliant member 450, an attachment fastener 470,and a pushrim tab 460 operating in connection with a sensor 480.

FIG. 13 shows an embodiment of a wheelchair 10 equipped with a motionassistance system 100 and remote brakes 490 that assist in turning. Theremote brakes 490 can be added to assist an operator with turning and/orbraking the wheelchair 10. The remote brakes 490 can be connected to themotion assistance system 100 via a wireless technology, for examplebluetooth technology. In this embodiment, a user can control thewheelchair 10 speed and direction using a control mechanism, such as ajoystick (not shown). The joystick can be mounted to a structuralelement or the frame of a wheelchair 10 in a similar manner to theremote control shown in FIG. 7. The remote brakes 490 can be used inconjunction with the pushrim control 400 to amplify the turning force onthe wheels. In certain embodiments, the remote brakes 490 can beactivated by rearward braking, based on a brake time, a brake force, ora rearward displacement, for example. In certain embodiments, the remotebrakes 490 can be turned off so that the system can operate like astandardized wheelchair.

Certain embodiments of the present technology also provide a motionassistance system that utilizes a mounting mechanism that is anexpanding connector bar that is attachable and/or detachable to one ormore structural elements of a wheelchair. FIG. 14 shows a rear angledview of a wheelchair 10 with the right wheel removed, the wheelchairequipped with a motion assistance system 100 attached by an expandingconnector bar 500 mounting mechanism. Similarly, FIG. 15 shows a rearview of a wheelchair 10 having a motion assistance system 100 attachedby an expanding connector bar 500. The expanding connector bar 500 cancomprise a spring element or other compressible bar element that causesthe connector bar 500 to generate an expanding force when thecompressible bar is in a compressed position.

The expanding connector bar 500 can have connection elements 570 on theend of the bar that are adapted to connect, mate, interlock, connectwith, or otherwise be held in place by structural elements of thewheelchair 10, or the wheelchair frame 70. The connector bar 500 canhave connection elements 570 that are adapted to connect with and beheld in place by corresponding elements located between the tips ofquick release axles 80 of the wheelchair 10, for example. In thismanner, the spring or compressible bar element of the connector bar 500can exert an expanding force against each of the corresponding elementsof the wheelchair 10. Similarly, to remove the motion assistance system,a user can compress the expanding connector bar 500, and remove themotion assistance system 100 from the wheelchair 10. In someembodiments, the motion assistance system 100 can be connected to, anddisconnected from a battery 30, a wheelchair power source, and/orwheelchair control system via an electric power connector 21, forexample.

The expanding connector bar 500 can also comprise a hand friction lock510, which can be used to prevent the connector bar 500 from compressingwhen the motion assistance system 100 is installed on a wheelchair 10.For example, the friction lock 510 can be toggled into a locked positionthat prevents the connector bar 500 from compressing when the motionassistance system is in use, so that the motion assistance system 100cannot separate from the wheelchair 10 during operation. The connectorbar 500 can also comprise a semi-permanent adjustment lock 520, whichmay only be adjusted or toggled, for example, using a tool such as a keyor a pin.

In certain embodiments, the expanding connector bar 500 serves as themounting mechanism of the motion assistance system. The expandingconnector bar 500 can also be attached or attachable to the drive unit102, at an end location of the drive linkage 120, for example. In thismanner, the motion assistance system 100 can be easily attached anddetached from a wheelchair 10 for easy storage, transportation, and use.In some embodiments, the expanding connector bar 500 can be adapted tooperate with a folding frame wheelchair, or a wheelchair that can becollapsed or compressed for storage and/or transport.

The present technology has now been described in such full, clear,concise and exact terms as to enable any person skilled in the art towhich it pertains, to practice the same. It is to be understood that theforegoing describes preferred embodiments and examples of the presenttechnology and that modifications may be made therein without departingfrom the spirit or scope of the invention as set forth in the claims.Moreover, it is also understood that the embodiments shown in thedrawings, if any, and as described above are merely for illustrativepurposes and not intended to limit the scope of the invention. As usedin this description, the singular forms “a,” “an,” and “the” includeplural reference such as “more than one” unless the context clearlydictates otherwise. Finally, all references cited herein areincorporated in their entirety.

The invention claimed is:
 1. A motion assistance system for a wheelchaircomprising: a mounting mechanism that is attachable to a structuralelement of the wheelchair; a drive linkage removably connectable to themounting mechanism, the drive linkage being pivotable with respect tothe mounting mechanism when connected to the mounting mechanism; a drivewheel mounted to an end of the drive linkage such that the drive wheelcontacts the ground when installed on the wheelchair; a remote controlthat controls the drive wheel and that includes a sensor, wherein whenthe sensor detects movement, the control directs the drive wheel toaccelerate, and when the wheelchair has accelerated to a desired speed,the remote control can be operated to stop the drive wheel from furtheracceleration and continue cruising at the desired speed.
 2. The systemof claim 1, wherein the rate of acceleration is based on the amount offorce used to create the movement.
 3. The system of claim 1 furtherincluding a wearable band that can be used to operate the remotecontrol.
 4. The system of claim 1, wherein the drive wheel comprises aplurality of lateral rollers positioned radially about the circumferenceof the power drive wheel, wherein the lateral rollers are rotatableabout an axis tangential to the circumference of the drive wheel.
 5. Thesystem of claim 1, wherein the remote control deactivates the drivewheel upon sensing the wheelchair wheel being pushed rearward.
 6. Thesystem of claim 1, wherein the remote control decelerates the drivewheel upon sensing the wheelchair wheel being pushed rearward.
 7. Thesystem of claim 1, wherein the drive linkage includes a drive unitconnected to the drive wheel, and the drive unit is wirelessly connectedto the remote control.
 8. The system of claim 1, wherein the mountingmechanism includes a clamp that can be mounted to a bar on thewheelchair.
 9. The system of claim 1, wherein the drive linkage includesa hook that engages a hitch of the mounting mechanism.